Solid state light sources offers benefits over traditional incandescent and fluorescent lighting in some applications. The robustness, reliability and long life of light-emitting diodes (LEDs) are examples of these benefits. Currently, the intensity output of solid state light sources, such as LEDs, varies according to factors such as temperature, age, and date of manufacture. Consequently, conventional luminaires based on solid state sources do not maintain desired intensity and/or color during their lifetime.